This invention relates to an apparatus and method for winding a ribbon of reproducibly stored information such as magnetic tape of the type used in recording and playback machines. The winding system of the invention finds particular application in the manufacture of continuous loop cartridges such as 8-track tape cartridges. This invention also relates to the ribbon of reproducibly storable information so wound.
In the tape recording industry, particularly that aspect thereof that produces audio programs for consumer entertainment purposes, three familiar tape formats compete vigorously in the marketplace. These formats include the so-called reel-to-reel format, the cassette, and the 8-track cartridge. The reel-to-reel format utilizes a supply reel, on which a tape containing recorded program material is wound. To hear the program material the tape is conventionally fed past a playback head and collected on a takeup reel. After the program has been completed, the tape is ordinarily rewound onto the supply reel.
The cassette is a miniaturized self-contained reel-to-reel system. Like the reel-to-reel format, the casette has a supply reel and a takeup reel adapted to wind and rewind tape carrying recorded program material. The reels, however, are ordinarily enclosed within a small plastic magazine, which is inserted in a specially adapted machine to achieve the playback or rewind modes.
Unlike the conventional reel-to-reel format or cassette, the continuous loop cartridge utilizes only a single reel for carrying tape on which program material is recorded. The tape is wound about the reel in a continuous loop by extracting one end of the tape from the most interior wind and splicing it to the free, outer end. The continuous reel is then conventionally inserted in a plastic magazine, somewhat larger in size than the cassette. A specially designed cartridge player is adapted to play the recorded material upon insertion of the cartridge.
Though the continuously wound 8-track cartridge has numerous advantages over both the reel-to-reel format and the cassette, particularly the fact that it does not have to be rewound after playback, it also suffers from several drawbacks. Among these drawbacks is the fact that the manufacture of 8-track cartridges requires a relatively large amount of labor per unit and has a relatively high reject ratio. This adds to the cost of the cartridges placed on the market, and as a result, the 8-track cartridge has not realized its maximum competitive potential.
Though manufacturing techniques vary, in general, 8-track cartridges are made by starting with a supply reel of tape having a plurality of identical programs recorded thereon. The tape is placed on a winding apparatus and one end is threaded past a capstan and onto an 8-track platform, referred to hereinafter as a takeup reel. Motors controlling the capstan, the takeup reel, and sometimes the supply reel are then energized, to pull tape from the supply reel to the takeup reel, until the first program is wound onto the takeup reel. After this has been accomplished, the motors are de-energized and the rotation of the reels is stopped.
At a point on the tape far enough beyond the end of the first program to provide sufficient slack, the tape is cut to provide a free outer end which, as explained above, is spliced to the interior end wound on the takeup reel. In order to make this splice, the interior end is pulled up from the center of the tape wound on the takeup reel, and attached to the free outer end by conventional means. The takeup reel, now carrying a continuously wound tape program, is then inserted into an 8-track magazine in a conventional manner.
In many prior art winding systems, the rate at which a program is wound from the supply reel to the takeup reel is relatively slow. As a result, the operator tends to become inattentive. Alternatively, the operator may be required to perform other tasks during the relatively slow winding period, thereby creating an inefficient expenditure of the operator's time and motion.
In addition to operator inefficiency, many winding systems of the prior art undesirably produce a uniformly tight wind on the takeup reel. Thus, in such systems the inner end of the tape can generally be pulled up from the center only with substantial difficulty. Moreover, oftentimes the tape crinkles when it is pulled, necessitating severance and disposal of the crinkled portion. Heretofore, the most common method for eliminating tight center winds on the takeup reel has been to reduce the torque of the takeup motor, thereby achieving a loose wind on the entire takeup reel. This is unacceptable, however, because a uniformly loose wind is generally achieved by entrapping air between the winds, which precludes precise correlation between the number of turns and the length of the tape program necessary to effect proper tensioning inside the completed cartridge. For example, too few turns for a given length of tape will inhibit tape movement inside the cartridge, resulting in sound distortion or jamming. On the other hand, too many turns for a given length of tape will cause tape spillage. Though it would appear that these problems could be circumvented by counting both the length of the program and the number of turns, this is also unacceptable because of the inherent variations in tape thickness. Thus, though a uniformly loose wind may facilitate tape pullout, it creates numerous other problems which themselves result in additional labor and a high reject ratio.
Operator inattentiveness, pullout difficulties, crinkling problems, winding inconsistencies and tape wastage all tend to increase the cost of manufacturing 8-track cartridges. Accordingly, it is the primary object of the invention to provide a tape winding apparatus and method which militate against the causes of these high manufacturing costs. More particularly, it is an object of this invention to provide a high speed tape winding system which requires minimal operator skill. It is also an object of this invention to produce a wound ribbon of reproducibly storable information having relatively loose center winds, thereby reducing pullout difficulties and minimizing tape crinkle and wastage, and tight noncenter winds which result in a more consistently wound product. A further object of the invention is to provide a tape winding system which achieves all of the above benefits without using a costly capstan or capstan motor, though, it will be seen that the invention can be practiced with a capstan and a capstan motor.